+#include "signature.h"
+SIGNATURE_CHECK (tdelete, void *, (void const *, void **,
+ int (*) (void const *, void const *)));
+SIGNATURE_CHECK (tfind, void *, (void const *, void * const *,
+ int (*) (void const *, void const *)));
+SIGNATURE_CHECK (tsearch, void *, (void const *, void **,
+ int (*) (void const *, void const *)));
+SIGNATURE_CHECK (twalk, void, (void const *,
+ void (*) (void const *, VISIT, int)));
+